The present invention relates to game balls, and more specifically to balls used on the games of pool and billiards.
Prior to the present invention, pool and billiard balls have become somewhat standardized both as to surface hardness and finish and as to diameter and weight. Within the constraints of these standards, it has heretofore been impossible to manufacture transparent balls for use in these games which would withstand the required impact with other balls, have a pleasant appearance, be properly weighted and have a center of gravity precisely centered at the ball's geometric center for providing uniform rolling characteristics for the ball in all directions. One of the most severe limitations in the prior art in regard to producing such a ball has been the inability of the prior art to provide a mold for properly molding the entire sphere of such a ball, and a proper centering mechanism for assuring that a weighted object could be precisely located at the geometric center of the ball within such a mold used for thermosetting resin. Since balls of this type are generally ground and polished to a near perfect spherical shape after initial molding, it is important that the ball, before grinding, be formed as nearly spherical as possible, so that the grinding operation will uniformly grind the entire outer surface of the sphere, leaving the weighted object at the geometric center of this sphere.
The prior art has not provided a method for precisely centering a weighted object within such a spherical ball, but rather has typically relied upon the use of materials of uniform density to avoid any possibility of eccentric weighting within the ball.
These constraints therefore have led to the inability of the prior art to provide a transparent game ball with a weighted, precisely centered, opaque center.